Practice Empirical Formula in Chemistry

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The chemical formula that shows the simplest whole-number ratio of atoms of each element present in a compound, obtained by dividing all subscripts by their.

The reduced fraction of atoms—smallest numbers that show the ratio.

Example 1

medium
A compound contains 40.0\% C, 6.7\% H, and 53.3\% O by mass. Determine the empirical formula.

Example 2

hard
A compound has empirical formula \text{CH}_2\text{O} and a molar mass of 180\,\text{g/mol}. Find the molecular formula.

Example 3

medium
A compound is 72.0\% Mg and 28.0\% N. Find the empirical formula.

Example 4

medium
A compound is 40.0\% carbon, 6.7\% hydrogen, and 53.3\% oxygen by mass. What is its empirical formula?
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